Fairy Shrimp: Tiny Creatures, Big Discoveries

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Fairy shrimp are fascinating aquatic creatures that inhabit temporary freshwater ecosystems, called vernal pools. These intriguing invertebrates showcase unique characteristics, such as a translucent body with colors like blue, green, or orange, depending on factors like age, diet, and the bacterial content of their environment [Field Station].

There are different species of fairy shrimp, including the conservancy fairy shrimp and the vernal pool fairy shrimp, with diverse features that set them apart. For example, male vernal pool fairy shrimp are distinct due to the shape of their second antenna, while the female’s third thoracic segment in the middle part of its body differentiates them from other species [U.S. Fish and Wildlife Service].

What Are Fairy Shrimp

Crustacean Family

Fairy shrimp are small, delicate invertebrates belonging to the branchiopoda crustacean family. They are closely related to other small aquatic creatures such as water fleas and brine shrimp.


Fairy shrimp can be found in temporary, fish-free water bodies like vernal pools. They thrive in these environments because they can avoid becoming fish food and escape predation from migrating birds which peak later in the season.

Appearance and Sizes

  • Translucent body
  • Color ranges from whitish to blue, green, orange, and red
  • Size: 0.12 to 1.5 inches (3 to 38 mm) in length
  • No hard outer shell

Fairy shrimp exhibit a variety of colors based on their age, diet, and the bacterial content of the water. They differ from other shrimp by lacking a hard outer shell and having distinct antenna shapes.

Feature Fairy Shrimp Other Shrimp
Shell No hard outer shell Hard outer shell
Size 0.12 to 1.5 inches Varies
Habitat Temporary, fish-free water bodies Varies

Fairy shrimp species can be differentiated by specific features such as the male’s second antenna and the female’s third thoracic segment. For example, the vernal pool fairy shrimp and the conservancy fairy shrimp differ in these aspects.

Life Cycle and Reproduction

Eggs and Cysts

Fairy shrimp produce eggs called cysts. The cysts are highly resistant and can remain dormant for years, allowing them to survive unfavorable environmental conditions. Some features of fairy shrimp cysts include:

  • Dormancy: Withstands extreme temperatures and drying
  • Hatching: Hatches when environmental conditions are favorable
  • Longevity: Can remain viable for multiple years

Hatching and Development

After hatching, fairy shrimp start their development as larvae called berra. They undergo a series of molts, gradually increasing in size. The development involves:

  • Multiple stages: Fairy shrimp pass through several growth stages before reaching maturity
  • Growth: Rapid growth occurs within a few weeks
  • Mating: Maturity is reached and mating occurs between males and females

A comparison of two common fairy shrimp species’ development times:

Species Time to Maturity Time to Reproduce
Vernal Pool Fairy Shrimp 18 days 40 days
Conservancy Fairy Shrimp 37 days 46 days


Fairy shrimp have a relatively short lifespan, which varies depending on the species. For example, the vernal pool fairy shrimp lives for an average of 91 days. They begin their life in vernal pools around November and complete their life cycle by early May.

Feeding and Nutrition

Filter Feeders

Fairy shrimp are filter feeders, using their legs to create water currents that help them capture food particles. They have the following features:

  • Well-adapted to their vernal pool habitats
  • Efficiently consume small particles in the water
  • Contribute to maintaining water quality

Diet Components

Fairy shrimp primarily consume the following:

  • Algae: A primary food source in vernal pools
  • Bacteria: Microscopic organisms present in their habitat
  • Protozoa: Single-celled organisms that float in the water
  • Detritus: Decaying organic matter, like fallen leaves and dead insects
Food Component Description
Algae Primary food source, provides energy and nutrients
Bacteria Microscopic organisms breaking down organic matter
Protozoa Tiny, single-celled organisms
Detritus Decaying plant and animal material

Feeding in Captivity

Feeding fairy shrimp in captivity requires replicating their natural diet as closely as possible. To do this, use the following:

  • Yeast soup: A mixture of yeast, sugar, and water
  • Fish food flakes: Crushed to a fine powder
  • Eyedropper or pipette: To carefully administer the food


  • Maintains the health and vitality of captive fairy shrimp
  • Can stimulate the growth and hatching of dormant cysts


  • Requires close monitoring of the water temperature and light conditions
  • May not completely replicate the breadth of their natural diet

Habitats and Distribution

Vernal Pools

Fairy shrimp inhabit seasonal vernal pools, where they live in shallow, fish-free water1. These temporary water bodies provide a unique ecosystem that helps fairy shrimp avoid predators such as fish and migratory birds2. Vernal pools are rich habitats for various types of grasses and other aquatic organisms, contributing to the overall ecology of the region.

Location and Range

Fairy shrimp are mainly found in specific regions of California, Oregon, and other parts of the United States. Some notable areas include:

  • Central Valley
  • Tehama County
  • Merced County
  • Ventura County3

The vernal pool ecosystems in areas such as Vina Plains, Glenn County, Solano County, and Stanislaus County are also home to a diverse range of fairy shrimp species4.

Threats and Conservation

Fairy shrimp face several threats, primarily due to habitat loss from factors like:

  • Agriculture
  • Urban development
  • Drought

As a result, some fairy shrimp species, such as Branchinecta conservatio, become endangered or threatened. Conservation efforts are ongoing, involving collaborations between organizations like the University of California and the government to protect habitats like the Grasslands Ecological Area and the Los Padres National Forest5.

Fairy Shrimp Their Habitat Threats
Vernal Pool Species Vernal Pools Agriculture
California Urbanization
Oregon Drought

With these conservation efforts in place, it is hoped that the unique habitats and ecosystems supporting fairy shrimp and other organisms can continue to thrive and contribute to the overall biodiversity of the region.

Fairy Shrimp as Pets

Housing and Tank Setup

Fairy shrimp are small crustaceans that thrive in temporary water bodies, like vernal pools. To create a suitable environment for these pets:

  • Use a spacious container or aquarium
  • Mimic their natural habitat with a substrate of soil, pebbles, or sand
  • Add aquatic vegetation and leaf litter as hiding spots
  • Ensure minimal water flow in the tank

Water Conditions and Maintenance

Fairy shrimp can adapt to a variety of water conditions, but certain parameters must be maintained:

  • Maintain water temperatures between 10 and 22°C (50-72°F)
  • Keep water salinity low, as they cannot tolerate high salt concentrations
  • Replace water partially every few days, or add aged water to maintain the tank’s balance
  • Avoid using water with chlorine, as it is harmful to fairy shrimp
  • Regularly check the overall health of your shrimp and monitor ammonia and nitrite levels in the water

Feeding and Care Tips

In the wild, fairy shrimp mostly feed on algae, bacteria, and microorganisms like rotifers. Here are some key feeding tips:

  • Purchase specialty fairy shrimp foods or use powdered algae and yeast as an alternative
  • Feed them small amounts several times a day to ensure optimal growth
  • Monitor their population to avoid overcrowding, as fairy shrimp can reproduce rapidly
  • Observe your shrimp’s behavior and adjust their diet accordingly if they appear stressed or unhealthy

It’s essential to note that certain species of fairy shrimp are endangered. Keeping them in captivity might be subject to legal restrictions. Research and comply with local regulations before acquiring these fascinating aquatic pets.

Interesting Facts and Species

Endangered and Threatened Species

The Fairy Shrimp have a few species that are considered endangered or threatened. Some examples of these species include the Vernal Pool Fairy Shrimp and the Conservancy Fairy Shrimp. These species are often found in vernal pools and their habitats are protected by organizations like The Nature Conservancy.

Unique Characteristics

  • Translucent body
  • Color varies based on factors like age, diet, and water conditions
  • No hard outer shell like other shrimp species
  • Inhabit fish-free vernal pools to avoid predators
  • Sensitive to water conditions like alkalinity and chlorine

Fairy Shrimp are fascinating creatures due to their unique characteristics. They are translucent and exhibit different colors based on factors such as age, diet, and bacterial content of the water. Unlike other shrimp species, these crustaceans do not have a hard outer shell. They thrive in fish-free vernal pools which allow them to avoid predators. Moreover, Fairy Shrimp are sensitive to changes in water conditions like alkalinity and chlorine levels.

Notable Examples

Vernal Pool Fairy Shrimp (Branchinecta lynchi)

  • Measures 0.12 to 1.5 inches in length
  • Distinct shape of the male’s second antenna
  • Unique third thoracic segment shape in females

Conservancy Fairy Shrimp (Branchinecta conservatio)

  • Found only in California’s Central Valley region
  • Restricted to vernal pools from Tehama County to Merced County
  • Named for The Nature Conservancy organization


  1. (https://uwm.edu/field-station/fairy-shrimp/)
  2. (https://uwm.edu/field-station/fairy-shrimp/)
  3. (https://www.fws.gov/species/vernal-pool-fairy-shrimp-branchinecta-lynchi)
  4. (https://ucmp.berkeley.edu/education/lessons/brine_shrimp.html)
  5. (https://www.fws.gov/species/vernal-pool-fairy-shrimp-branchinecta-lynchi)


  • Bugman

    Bugman aka Daniel Marlos has been identifying bugs since 1999. whatsthatbug.com is his passion project and it has helped millions of readers identify the bug that has been bugging them for over two decades. You can reach out to him through our Contact Page.

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  • Piyushi Dhir

    Piyushi is a nature lover, blogger and traveler at heart. She lives in beautiful Canada with her family. Piyushi is an animal lover and loves to write about all creatures.

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4 Comments. Leave new

  • The green on the gills is an alga, Rhopalosolen saccatus.

  • We have a weird bug here in Central Florida, along the Atlantic Coast. It is about an inch long, and a quarter inch wide. It is mostly white and looks like it has feathers, but those may be legs. There is some orange-red on its back. When watched, it will suddenly fly towards the watcher in a menacing manner. Not known if it bites or not. Can you help identify this insect?


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